Predictive value of diffusion-weighted imaging without and with including contrast-enhanced magnetic resonance imaging in image analysis of head and neck squamous cell carcinoma

Objectives: To assess disease-free survival (DFS) in head and neck squamous cell carcinoma (HNSCC) treated with (chemo)radiotherapy ([C]RT). Methods: Pretreatment MR-images of 78 patients were retrospectively studied. Apparent diffusion coefficients (ADC) were calculated with two sets of two b-values: 0-750 s/mm(2) (ADC(750)) and 0-1000 s/mm(2) (ADC(1000)). One observer assessed tumor volume on T1-WI. Two independent observers assessed ADC-values of primary tumor and largest lymph node in two sessions (i.e. without and with including CE-T1WI in image analysis). Interobserver and intersession agreement were assessed with intraclass correlation coefficients (ICC) separately for ADC(750) and ADC(1000). Lesion volumes and ADC-values were related to DFS using Cox regression analysis. Results: Median follow-up was 18 months. Interobserver ICC was better without than with CE-T1WI (primary tumor: 0.92 and 0.75-0.83, respectively; lymph node: 0.81-0.83 and 0.61-0.64, respectively). Intersession ICC ranged from 0.84 to 0.89. With CE-T1WI, mean ADC-values of primary tumor and lymph node were higher at both b-values than without CE-T1WI (p < 0.001). Tumor volume ( sensitivity: 73%; specificity: 57%) and lymph node ADC(1000) (sensitivity: 71-79%; specificity: 77-79%) were independent significant predictors of DFS without and with including CE-T1WI (P < 0.05). Conclusions: Pretreatment primary tumor volume and lymph node ADC1000 were significant independent predictors of DFS in HNSCC treated with (C)RT. DFS could be predicted from ADC-values acquired without and with including CE-T1WI in image analysis. The inclusion of CE-T1WI did not result in significant improvements in the predictive value of DWI. DWI without including CE-T1WI was highly reproducible. (C) 2014 Elsevier Ireland Ltd. All rights reserved.